关于WebView调用系统相册上传图片

[discovery] errors encountered while discovering extensions: Error Domain=PlugInKit Code=13 "query cancelled" UserInfo={NSLocalizedDescription=query cancelled}

出现这样额错误原因

As you mentioned, you need to add the webView.load(urlRequest); **only in viewDidLoad.
The reason is because calling the Library or Camera will open up the OS dialog to pick or take a photo, and once you are done doing that, your ViewController will call again the viewWillAppear and viewDidAppear callbacks and that will re-trigger your initial webview load (refreshing the page).
           

##翻译

正如您提到的，您需要添加webview.load（urlrequest）仅在viewdidload中。

原因是，调用库或照相机将打开操作系统对话框来选择或拍摄照片，一旦完成此操作，您的视图控制器将再次调用该视图，该视图将显示并显示回调，这将重新触发初始的WebView加载（刷新页面）。